Mining was quite important in the northern territory of Tonkin, and Chinese merchant organizations were heavily involved in there. As of the 1760s, taxes on Chinese mines accounted for roughly half the annual income of the Trinh lords.<ref>Robert Hellyer, ''Defining Engagement'', Harvard University Press (2009), 78-79.</ref> | Mining was quite important in the northern territory of Tonkin, and Chinese merchant organizations were heavily involved in there. As of the 1760s, taxes on Chinese mines accounted for roughly half the annual income of the Trinh lords.<ref>Robert Hellyer, ''Defining Engagement'', Harvard University Press (2009), 78-79.</ref> |